Energy-conversion apparatus and process

ABSTRACT

One embodiment of an energy-conversion apparatus includes a first container to contain working fluid under pressure, a first heat-transfer component in the first container, a second container to contain fluid under pressure, a second heat-transfer component in the second container, and an energy converter coupled to the first and second containers that performs work in response to a flow of fluid through the energy converter, wherein the flow is motivated by varying a pressure within the first container or within second container (or both) caused by the first heat-transfer component or the second heat-transfer component, respectively, without a need for heat conduction through an exterior surface of either container. An energy-conversion method includes, from within one or both of first or second containers, varying an internal temperature to cause a resultant pressure differential that motivates the fluid to flow between the first and second containers, and performing work as fluid flows through the energy converter between the containers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application claims the benefit of U.S. Provisional Application No.60/868,709, filed on Dec. 5, 2006.

INTRODUCTION

Non-renewable sources of energy generation, such as oil and coal, riskdepletion. Other sources of energy, such as hydroelectric dams andnuclear facilities, present actual or potential environmentalconsequences. There is a continuing need to garner usable energy fromrenewable, environmentally sensitive sources that utilize, for example,solar radiation and geothermal technologies.

SUMMARY

The present invention is defined by the claims below. But in summaryfashion, embodiments of the invention provide a way to convertrenewable, environmentally sensitive sources of energy, such as solarradiation and geothermal technologies, as well as non-renewable sourcesof energy, such as natural gas, into more readily usable forms ofenergy, such as electricity. Pressure differentials between containersare used to motivate exchanges of a working fluid between thecontainers, which, in turn, are used to stimulate an energy converterand perform work. Work includes any kinetic response to a flow ofworking fluid, and also includes generating electricity. Heating andcooling of the working fluid takes place from within the containersrather than requiring heat conduction through the container shells, thusreducing parasitic heat losses and, therefore, enhances efficiencies.

In a first aspect, an energy-conversion apparatus includes a containerto contain working fluid under pressure, a heat-transfer component inthe first container; another container to contain working fluid underpressure; and an energy converter coupled to the containers thatperforms work in response to a flow of working fluid through the energyconverter. The flow is motivated by varying a pressure within the firstcontainer caused by the first heat-transfer component.

In a second illustrative aspect, an energy-conversion apparatus includesa first container to contain working fluid under pressure, a firstheat-transfer component in the first container that can manipulate aninternal temperature of the first container (first internal temperature)from within the first container, a second container to contain workingfluid under pressure, a second heat-transfer component in the secondcontainer that can manipulate an internal temperature of the secondcontainer (second internal temperature) from within the secondcontainer, and an energy converter coupled to the first and secondcontainers that performs work in response to a flow of working fluidbetween the containers.

In a third illustrative aspect, an energy-conversion apparatus includesa first container of working fluid under pressure, a first heat-transfercomponent in the first container and that can manipulate an internaltemperature within the first container without a need for heatconduction through an exterior surface of the first container, a secondcontainer of working fluid under pressure coupled to the firstcontainer, a second heat-transfer component in the second container thatcan manipulate an internal temperature within the second containerwithout a need for heat conduction through an exterior surface of thesecond container; and an energy converter coupled to the containers andthat can perform work in response to a flow of the working fluid betweenthe containers.

In a fourth illustrative aspect, an energy-converting apparatus includesa first containment means for containing a first supply of working fluidunder pressure, a first heat-varying means in the first containmentmeans for changing a temperature within the first containment means, asecond containment means for containing a second supply of working fluidunder pressure, a second heat-varying means in the second containmentmeans for changing a temperature within the second containment means,and a means for converting energy in response to a flow of working fluidbetween the first and second containment means, and vice versa, urged bya difference in pressure between the containments, which is induced byutilizing at least one of the first or second heating means to changethe temperature within at least one of the first or second containments.

In a fifth illustrative aspect, an energy-conversion apparatus includesa first container to contain working fluid under pressure, a first inletport that allows heat-transfer fluid to be introduced into an interiorof the first container, a second container to contain working fluidunder pressure, and an energy converter coupled to the first and secondcontainers that performs work in response to a flow of working fluidthrough the energy converter. The flow is motivated by internallyvarying a pressure within the first container caused by direct heattransfer between the heat-transfer fluid and the working fluid.

In a sixth illustrative aspect, an energy-conversion apparatus includes:a first container of working fluid under pressure; a second container ofworking fluid under pressure coupled to the first container; a firstheat-transfer component in the first container that, without a need forheat conduction through an exterior surface of the first container, canperform one or more of (1) internally increase a temperature within thefirst container above a temperature within the second container, and/or(2) internally decrease a temperature within the first container below atemperature within the second container; and an energy converter coupledto the first container and to the second container and adapted toperform work in response to a force exerted upon it. The force can becreated as a result of a change in pressure in at least the firstcontainer caused by an internal manipulation of an internal temperaturewithin at least the first container.

In a seventh illustrative aspect, an energy-conversion apparatusincludes a first container to contain working fluid under pressure thathas an inlet port, a second container to contain working fluid underpressure, an energy converter coupled to the containers that performswork in response to a flow of working fluid through the energyconverter. The flow is motivated by internally varying a pressure withinthe first container caused by varying a temperature of the working fluidin at least the first container.

In an eighth illustrative aspect, a method for converting energy byutilizing a system comprising first and second containers to containworking fluid under pressure coupled to an energy converter is provided.One embodiment of the method includes from within one or both of thefirst and second containers, varying an internal pressure; andperforming work as the energy converter is stimulated in response to aflow of working fluid motivated to pass through the energy converter bythe varying internal pressure. The varying of the internal pressureincludes effecting a temperature change from within the first container,thereby causing a resultant change in pressure.

In a ninth illustrative aspect, a method for converting energy includes,from within a first or second container, varying an internal temperatureto cause a resultant pressure differential that motivates working fluidto flow between the containers, and performing work as working fluidflows through the energy converter between the containers in response tothe pressure differential.

In a tenth illustrative aspect, a method for converting energy asworking fluid flows between a first container that contains workingfluid under pressure and a second container that contains working fluidunder pressure includes stimulating an energy converter by inducing afluid-exchange cycle through the energy converter by varying thepressure of at least one of the containers relative to the other byinternally varying the temperature of the working fluid of at least oneof the containers.

In an eleventh illustrative aspect, a method for converting energyincludes providing a first a container to contain working fluid underpressure (the first container substantially surrounding a firstheat-transfer component that can internally change an internaltemperature within the first container), providing a second container tocontain working fluid under pressure (it substantially surrounding asecond heat-transfer component that can internally change an internaltemperature within the second container), providing an energy convertercoupled to the first container and to the second container, stimulatingthe energy converter with a flow of working fluid from the firstcontainer to the second container by internally varying a pressurewithin the first or second container by varying a temperature within thefirst or second container so that a first pressure differential betweenthe two containers is sufficiently high that it motivates the flow untilthe differential pressure between the two containers reaches a desiredlow pressure differential, and increasing the desired low pressuredifferential to a second sufficiently high pressure differential so asto motivate a flow of the working fluid from the second container to thefirst container by varying a temperature within the first or secondcontainers.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Illustrative embodiments of the present invention are described indetail below with reference to the attached drawing figures. In thefigures, hatching generally represents heat-transfer fluid. The drawingsare incorporated by reference herein, and wherein:

FIGS. 1A-1B depict several phase diagrams of an embodiment of thepresent invention;

FIGS. 2A-2D depict a more detailed illustration of various stages thatan embodiment of the present invention passes through to convert otherforms of energy into electricity;

FIGS. 3A-3D are additional simplified diagrams depicting high-levelaspects of the invention;

FIGS. 4A-4D are additional simplified diagrams depicting high-levelaspects of the invention;

FIG. 5 depicts an illustrative method for practicing an embodiment ofthe present invention;

FIG. 6 depicts still a more detailed illustrative operating environmentsuitable for practicing an embodiment of the present invention;

FIG. 7 depicts another illustrative system utilizing directheat-transfer techniques according to an embodiment of the presentinvention; and

FIG. 8 depicts an illustrative system utilizing a piston apparatusaccording to an embodiment of the present invention.

DETAILED DESCRIPTION

As briefly mentioned, embodiments of the present invention provide a wayto convert renewable, environmentally sensitive sources of energy, suchas solar radiation and geothermal technologies, as well as non-renewablesources of energy, such as natural gas, into more readily usable formsof energy, such as electricity. One or more heat transfer components aresituated within the interior of two or more containers and are utilizedto vary a temperature of at least a portion of an enclosed workingmedium to develop a pressure differential between portions of themedium. The pressure differential can be used to motivate a flow of theworking medium that can, in turn, be used to motivate a motive powersource/perform work/generate energy (such terms are used substantiallyinterchangeably herein).

Turning now to FIGS. 1A and 1B, several phase or state diagrams aredepicted that illustrate various aspects of an embodiment of the presentinvention. Turning first to FIG. 1A, and more specifically to thebeginning of Phase I illustrated generally by reference numeral 110, afirst container 112 is adapted to contain a quantity of working fluid114 under pressure. First container 112 and second container 116 aredepicted illustratively as spherical in shape, of equivalent volume, andas separate structures. However, such depiction should not be construedas limitations of the present invention. To the contrary, firstcontainer 112, as well as second container 116 may take on a variety offorms. For example, the shapes may be round, cylindrical, or othermanmade design, or even take the form of natural caverns or caves to theextent they can be adapted to contain fluid under pressure. It is notnecessary that the containers be of equivalent volume and may compriseportions of a single overall structure.

Relative quantities of working fluid in the containers are generallyrepresented by dots (e.g., FIG. 1 through FIG. 4). These dots areprovided to illustratively help understand various embodiments of thepresent invention, and should not be confused with indicating either anabsolute mass or a relative pressure. Moreover, differences areexaggerated for illustrative purposes to indicate relative quantitydifferences. Indeed, under certain conditions, one container may containa greater mass of working fluid than the other container, but because oftemperature differences, they may be at the same pressure, or it mayalso be the case that the container with the relatively less workingfluid is actually at a greater pressure than the other container. Notall drawings depict working fluid as dots (e.g., FIG. 6) so as to notobscure certain aspects of some embodiments of the present invention.Moreover, some drawings (e.g., FIG. 7 and FIG. 8) use dots to depictheat-transfer fluid rather than working fluid, which is identified, butnot visible by markings.

Second container 116 contains an amount of working fluid 118 underpressure. As will be explained in greater detail below, the workingfluid of each container will flow between the containers, but separatereferenced numerals are provided so as to facilitate an easierexplanation of an embodiment of the present invention. Working fluid 114and working fluid 118 may be a gas, vapor, mixture of gases, and thelike. As used herein, the term “fluid” used in connection with “workingfluid” is not necessarily limited to mean a gas alone, but may be acombination of gas and liquid in certain situations.

Two sources of heat-transfer fluid are shown. A first source ofheat-transfer fluid is referenced by numeral 120, and is relativelyhotter than a second source of heat transfer fluid 122, which isrelatively cooler than hotter heat-transfer fluid 120. Heat-transferfluid 120 and heat-transfer fluid 122 may be a liquid, gas, vapor, andthe like. As used herein, the term “fluid” used in connection with“heat-transfer fluid” is not necessarily limited to mean a gas alone ora liquid alone, but may be a combination of gas and liquid in certainsituations. For ease of reading purposes, “heat-transfer fluid” will beabbreviated as “HTF.” HTF should not be construed as hot or cold per se.Rather, as the name suggests, it is a fluid that is used to communicateor transfer a level of heat. This can refer to a process of emitting orintroducing heat or to a process of absorbing or withdrawing heat.

Several instruments, valves, gauges, control mechanisms etc., are notshown in the phase diagrams of FIGS. 1A and 1B because these diagramsare meant to provide a high-level overview of the way that an embodimentof the present invention functions. More detail surrounding thesevarious omitted items will be provided below. But an illustrative valve124 is shown coupled to an energy converter 126, which generateselectricity itself or is coupled to a generator 128. In otherembodiments it may be a piston. In Phase I, valve 124 depicts a closedposition. That is, the working fluid contained in each of the containersis not allowed to flow between the containers. Conduit 130 provides aflow path through which either working fluid 114 could flow, ifmotivated, from first container 112 through valve 124, if open, energyconverter 126, and into second container 116 or, alternatively, workingfluid 118 could flow, if motivated, from second container 116 throughenergy converter 126 and valve 124, if open, and into first container112. Also simplified in the diagrams of FIGS. 1A and 1B are theconnections to a turbine or other energy converter 126. Energy converter126 may be a turbine, but may also be other forms of energy-generationdevices that can generate energy or perform work in response to a flowof fluid between the two containers (for example, a piston). In someembodiments, the energy converter is not a piston. An example of thesimplification depicted in diagram 110 is that a single inlet and egressis shown regarding energy converter 126. But it is contemplated withinthe illustration that subchannels may actually exist within conduit 130.This would be the case if it is desired that energy converter 126 rotatein the same direction during each fluid-exchange cycle. In such a case,a specialized turbine, such as a warm-drive turbine, could be employedthat utilizes a single flow path, or dual flow paths could be providedso that working fluid can flow through a first path and cause rotationin a first direction, but flow in a second path during a reverse cycleand still cause energy converter 126 to rotate in the same directionthat it did as working fluid flowed through the first path.

Structure 132 indicates that hotter HTF 120 is introduced within firstcontainer 112 to warm working fluid 114. Structure 132 is depicted in anillustrative sense to indicate that working fluid 114 is exposed,directly or indirectly, to hotter HTF 120 from a disposition within theinterior of first container 112. Structure 132 may take on a variety offorms, including conduit, or coils of conduit, made out of aheat-conducting material, such as copper or aluminum. In otherembodiments, structure 132 may take the form of an inner wall of firstcontainer 112. In still other embodiments, the hotter HTF is allowed tocome into direct contact with the working fluid and to transfer heatwithout being contained in a conduit or other component via theintroduction of the hotter HTF through a port or other inlet in the wallof container. Although shown separately, another structure 134 can beused to allow working fluid 114 to be exposed to the effects of coolerHTF 122. In some embodiments, structures 132 and 134 are one and thesame. They are shown separately merely to help facilitate an easierunderstanding of an embodiment of the present invention.

Similarly, structure 136 can be used to expose working fluid 118 to theeffects of hotter HTF 120 in second container 116. And structure 138 canbe used to introduce cooler HTF 122 into an interior of second container116 so that it can withdraw heat from working fluid 118.

Four legends are shown in diagram 110: a first pressure legend 140, afirst temperature legend 142, a second pressure legend 144, and a secondtemperature legend 146. These are referred to as legends because theyare not necessarily actually gauges. This is why no lines are shownconnecting the legends to the containers. Although in some embodiments,the respective containers are associated with gauges, such as pressuregauges and temperature gauges, the legends are shown to help the readerunderstand the happenings during the illustrative phases of anembodiment of the present invention. For example, first pressure legend140 merely indicates a relatively moderate starting pressure associatedwith the interior of first container 112. Similarly, first temperaturelegend 142 indicates that a relatively low temperature is initiallyassociated with working fluid 114 at the beginning of Phase I. Secondpressure legend 144 indicates that a relatively moderate startingpressure is also associated with working fluid 118, and secondtemperature legend 146 indicates that a relatively high temperature isinitially associated with working fluid 118 at the beginning of Phase I,110. The various indications are not intended to represent actualquantified pressures and temperatures, but are merely provided toindicate relative variances as the various phases are progressedthrough.

At the beginning of Phase I, hotter HTF 120 begins to circulate throughstructure 132 in such a way that it introduces heat into working fluid114. At the same time, cooler HTF 122 is introduced via structure 138 tothe interior of second container 116 in such a way that it withdrawsheat from working fluid 118. An explanation in greater detail will beprovided below as to how hotter HTF 120 attains its heat and how coolerHTF 122 attains its relative coolness. But summarily, in one embodiment,a conglomeration of reflecting devices, such as parabolic mirrors, canbe used to concentrate and direct sunlight to one or more reservoirsthat contain a portion of hotter HTF 120 so that it is heated. Thisprocess has been used to substantially heat fluids, such as oil or oilrelated substances. In one embodiment, geothermal processes are utilizedto cool HTF 122.

Arrow 148 reflects a transition to an ending stage associated with PhaseI and referenced generally by the numeral 150. At the end of Phase I,the pressure inside first container 112 a is higher than what it was atthe beginning of Phase I. This relatively higher pressure is indicatedby first pressure legend 140 a. The relatively higher pressure wascaused by virtue of introducing heat into working fluid 114 a by way ofhotter HTF 120 a. This relative increase in temperature is representedby first temperature legend 142 a, depicting a relatively highertemperature than that of the beginning of Phase I. The pressure insecond container 116 a has dropped below what it was at the beginning ofPhase I, indicated by second pressure legend 144 a, and a temperature ofworking fluid 118 a is relatively lower than it was at the beginning ofPhase I, which is indicated by second temperature legend 146 a. Therelatively lower pressure and temperature was caused by virtue ofwithdrawing heat from working fluid 118 a by way of cooler HTF 122 a.Valve 124 a is still closed at the end of Phase I. At this point,working fluid has not been allowed to be exchanged between the twocontainers.

Arrow 152 reflects a transition from the end of Phase I to the beginningof Phase II, which is referenced generally by the numeral 154. At thebeginning of Phase II, valve 124 b (which is the same as valve 124 a andvalve 124, but is given a unique reference numeral to facilitateexplanation) is depicted in an open position, thereby allowing workingfluid 114 b to flow from first container 112 b into second container 116b. This flow is indicated by arrow 155 b. This flow is motivated by arelatively higher pressure within first container 112 b at the beginningof Phase II, as indicated by first pressure legend 140 b, than therelatively lower pressure within second container 116 b, as indicated bysecond pressure legend 144 b. As working fluid 114 b flows throughenergy converter 126 b it causes energy converter 126 b to rotate andthereby generate useable energy. Energy converter 126 b could be agenerator and generate electricity itself or could be another type ofmotive power device, such as a turbine, and be coupled to generator 128b, or could supply motive power to any other applicable device toperform any other suitable type of work. Hotter HTF 120 b can be allowedto continue to be circulated within an interior of first container 112 bduring Phase II so as to attempt to add additional heat energy to theworking fluid 114 b within first container 112 b to prolong oraccentuate a relative pressure differential between the two containersduring the fluid exchange from first container 112 b to second container116 b. Similarly, cooler HTF 122 b can be continued to be allowed to beexposed to working fluid 118 b during Phase II. The fluid-exchange cycleis allowed to continue until a desired minimum pressure differentialbetween the two containers is reached. Transition arrow 156 indicates atransition from the beginning of Phase II to the ending of Phase II,which is referenced generally by the numeral 158. At the end of PhaseII, the pressures in each of the containers are relatively near eachother, which are indicated by first pressure legend 140 c and secondpressure legend 144 c.

Turning now to FIG. 1B, the next state that is illustrated is thebeginning of Phase III, which is referenced generally by the numeral160. As shown, valve 124 d is in a closed position, prohibiting anyworking fluid to be exchanged between the two containers. With valve 124d closed, hotter HTF 120 d is allowed to be circulated in such a waythat it effects or translates to working fluid 118 d in second container116 d. Similarly, cooler HTF 122 d is circulated within first container112 d so that it cools the remaining working fluid 114 d in firstcontainer 112 d.

It is worth noting that relative variances can be attributed to a partof the success of the present invention. That is, absolute temperaturesand pressures are not as relevant as relative temperatures andpressures; namely, temperatures and pressures of a given state relativeto temperatures and pressures of a prior state; or the pressure within agiven container relative to the pressure within another container.Recall that at the end of Phase II, a substantially equilibrium pressurestate had been reached wherein working fluid no longer passed from thefirst container to the second container. With valve 124 d closed inPhase III, the pressure in second container 116 d is allowed to increaserelative to the pressure at the end of Phase II, and the pressureassociated with first container 112 d is allowed to decrease relative tothe pressure at the end of Phase II. Such a state is reflected bynumeral 162, denoting an ending of Phase III.

Transition arrow 164 depicts a transition from the beginning of PhaseIII to the ending of Phase III. At the end of Phase III, the pressureand temperature in first container 112 e is relatively lower than whatit was at the beginning of Phase III. This state is indicated by firstpressure legend 140 e and first temperature legend 142 e. Valve 124 eremains closed. By virtue of the continued circulation of hotter HTF 120e, the pressure and temperature of working fluid 118 e in secondcontainer 116 e are both relatively higher than they were at thebeginning of Phase III, or the end of Phase II. The relatively higherpressure is indicated by second pressure legend 144 e, and a relativelyhigher temperature is indicated by second temperature legend 146 e.

At the end of Phase III, a pressure differential exists between theworking fluid in first container 112 e and the working fluid in secondcontainer 116 e. Whenever a sufficient pressure differential exists, theenergy converter 126 e and generator 128 e can be stimulated to generateelectrical energy. Thus, arrow 166 indicates a transition to thebeginning of Phase IV, which is referenced generally by the numeral 167.At the beginning of Phase IV, valve 124 f is opened up so that workingfluid 118 f is allowed to flow from second container 116 f throughenergy converter 126 f into first container 112 f. This flow isillustrated by arrow 155 f. In one embodiment, hotter HTF is allowed tocontinue to circulate within an interior of second container 116 f whilecooler HTF 122 f is allowed to circulate within an interior of firstcontainer 112 f. The fluid-exchange cycle is allowed to continue untilthe two pressures between the two tanks become sufficiently relativelyclose to each other, which signals the ending of Phase IV.

Arrow 170 reflects a transition from the beginning of Phase IV to theending of Phase IV, which is referenced generally by the numeral 172.The ending of Phase IV is substantially similar to the beginning ofPhase I except that valve 124 g is shown open. Valve 124 g is shown opento allow any motivated fluid remaining in second container 116 g to flowinto first container 112 g. At a desired point, valve 124 g is closed,which state is reflected as the beginning of Phase I, 110.

The cycle can then be repeated an indefinite number of times. FIGS. 1Aand 1B have provided a high-level overview of an illustrative operatingenvironment of the present invention. Renewable energy sources, such asheat from the sun or coolness of the earth, or other sources of heatingand cooling, such as natural gas or heat pump technologies, are used insuch a way as to alternatively heat and cool a working fluid between twocontainers from the inside of the containers so that relative pressuredifferentials between the two containers can be used to motivateexchanges of fluid between the two containers that stimulates a motivepower source, such as a turbine to generate useable electricity orperform other work. Resulting electricity can be used immediately orstored at a later time using a technology such as batteries, waterlifting, a capacitive bank, compressing gas, or the like.

Turning now to FIG. 2A, another operating environment suitable forpracticing an embodiment of the present invention is provided andreferenced generally by the numeral 200. As shown, this embodimentdepicts in greater detail various valves, monitoring equipment, andother devices that can be employed to convert energy such as solarenergy into useable electricity. A parabolic mirror 210 directs sunlightto a receiver tube 212 that contains hotter HTF 214. Although not shown,a series of parabolic mirrors could be used to concentrate additionalsunlight at receiver tube 212 so as to provide additional heat energy tohotter HTF 214. A reservoir 216 may be used to store an amount of hotterHTF 214. A pump 218 can be used to circulate hotter HTF 214 through aninterior of a first container 220. During circulation, valves 222 and224 are positioned in such a way that fluid can circulate through thevarious conduit sections, as illustrated. As hotter HTF 214 circulatesthrough an interior of first container 220, it warms working fluid 226.Although an inner conduit 228 is shown as disposed within firstcontainer 220, in some embodiments it may form an inner wall of firstcontainer 220.

Another reservoir 230 can be used to contain cooler HTF 232. In oneembodiment, reservoir 230 is disposed sufficiently within the earth(ground or water) so that the earth acts as a heat path to maintaincooler HTF 232 at a substantially constant, relatively coolertemperature. In another embodiment, reservoir 230 is not so much areservoir as it is a series of conduit tubing that runs deep undergroundor underwater so as to allow heat to be leaked off into the earth, whichagain helps maintain a relatively cooler temperature of cooler HTF 232.

A pump 234 motivates cooler HTF 232 to circulate within an interior ofsecond container 236 to withdraw heat from a second supply of workingfluid 238. Pump 234 motivates fluid flow when valves 240 and 242 arepositioned in such a way as to direct cooler HTF 232 through the conduitshown and into the interior of second container 236 as represented bystructure 244, which is shown as being within second container 236. Heattransfer fins 246 and 248 can be used to further facilitate the transferof heat into or out of the respective working medians. During thisstage, a main valve 250 is closed to prevent working fluids 226 and 238from flowing between the containers.

A computerized controller 252 is coupled to a variety of sensing devicesthat are used to receive data that is used to control the various pumpsand valves to help optimize an efficiency associated with the variousphases, stages, and fluid-exchange cycles. For example, controller 252is coupled to a first pressure gauge 254 associated with first container220 as well as a first temperature gauge 256 also associated with firstcontainer 220. Similarly, controller 252 is coupled to a second pressuregauge 258 associated with second container 236, as well as a secondtemperature gauge 260 also associated with second container 236. Theserespective temperature and pressure gauges can be used to monitor therespective temperatures and pressures associated with the respectiveworking fluids of the containers. Similarly, the attributes of theheat-transfer fluids can also be monitored. For example, a first HTFtemperature gauge 262 and a second HTF temperature gauge 264 monitorstemperature associated with the HTFs in this embodiment.

Armed with input from one or more of these devices, controller 252 cancontrol the various pumps and valves and regulators. For example,controller 252 is coupled to a first HTF pressure regulator 266 as wellas to a second HTF pressure regulator 268. The HTF pressure regulatorscan regulate the pressure associated with the heat-transfer fluids toreduce the difference in pressure between the interiors of theheat-transfer conduits and the interiors of the containers in order toreduce the risk that the conduits may collapse or erupt (this may alsoenhance overall energy efficiency as the required strength and,therefore, thickness of the conduit walls may be reduced). Moreover,controller 252 is coupled to the various pumps and valves so as to allowthe circulation of the HTF when desired.

When fluid is allowed to be exchanged between the two containers, aturbine 270 is used to produce motive power for a generator 272 which,in turn, generates electrical energy. Controller 252 may also be coupledto a working-medium pressure regulator 274 to regulate pressure betweenthe two containers.

This state in FIG. 2A is allowed to persist until a desired pressuredifferential develops between the two containers. When a desiredpressure differential exists between the two containers, main valve 250can be opened, as shown in FIG. 2B, to allow an exchange of workingmedium between the two containers through pathway 276 in FIG. 2B.

During the state of FIG. 2B, electricity is generated as turbine 270 andgenerator 272 stimulated by the flow of fluid between the containers.This flow can be allowed to continue until the pressure differentialbetween the two containers is reduced to a threshold level. Thisthreshold level may occur by virtue of controller 252 imposing arestriction, or may occur by virtue of the fluid flowing from secondcontainer 236 into first container 220. Regarding the masses of workingfluid illustratively depicted in FIG. 2B (as well as FIG. 2D), noteshould be taken that those figures depict a transitionary state. When asmuch working fluid flows from first container 220 into second container236 as is desired, controller 252 can close main valve 250, which isrepresented by FIG. 2C.

In FIG. 2C, main valve 250 is shown to be closed. Having just reached anear equilibrium state, the two containers are now allowed to againdevelop a pressure differential with respect to each other. This occursby warming the working fluid 238 in second container 236 while coolingworking fluid 226 in first container 220.

Working fluid 238 is heated by receiving the effects of heat transferfrom the circulation of hotter HTF 214 being circulated within aninterior of second container 236. In one embodiment, controller 252stimulates pump 234 to motivate a circulation of hotter HTF 214 afterhaving positioned valves 222 and 240.

With continuing reference to FIG. 2C, controller 252 can also controlpump 218 and valves 224 and 242 to cause a circulation of cooler HTF 232within an interior of first container 220 so that its cooling effectsare translated to working fluid 226 in first container 220.

In this embodiment, first and second containers 220 and 236 are providedfirst and second insulations 278 and 280, respectively, to inhibit theeffects of ambient temperature from being translated to or from theworking fluids 226 and 238 within the containers. The working fluids 226and 238 are warmed and cooled from the inside of the respectivecontainers, not from the outside (aside from parasitic heat transfers toor from the ambient).

During this time, controller 252 can monitor the temperatures andpressures of both working fluids as well as both heat-transfer fluids aspreviously described.

The warmer the working medium within second container 236 gets, thegreater the pressure is developed. Similarly, the cooler the workingfluid 226 becomes within first container 220, the lower the pressurebecomes. This creates a relative pressure differential between the twocontainers that can be used to motivate an exchange of working fluidfrom second container 236 back to first container 220. This situation isrepresented in FIG. 2D.

Turning now to FIG. 2D, main valve 250 is shown to be open, and pathway276 is shown to include a quantity of working fluid which represents aflow of working fluid 238 from second container 236 into first container220. As the working fluid flows from a first container to a secondcontainer, turbine 270 is stimulated, which, in turn, stimulates agenerator 272 that generates electricity in one embodiment. Controller252 monitors the pressures and temperatures associated with the workingfluid of each container as well as the temperature and pressuresassociated with each of the heat-transfer fluids in one embodiment. Thisfluid-exchange cycle is allowed to continue for as long as there is asufficient pressure differential between second container 236 and firstcontainer 220 to motivate working fluid 238 to flow into first container220. At the end of this cycle, main valve 250 can be closed and thestate of FIG. 2A is reached, and the process can start all over again.

Turning now to FIG. 3A, another simplified view of a high-level overviewof the present invention is shown. In this embodiment, warmer HTF 312 iscirculated by heat-conducting structure 314 in an interior of firstcontainer 316 to warm working fluid 319. A layer of insulation 318 isshown to reduce the effects of ambient temperature on working medium319.

A supply of cooler HTF 320 is circulated by way of a heat-conductingstructure 322 in an interior of second container 324 to cool a secondsupply of working medium 326 inside second container 324. Variousvalves, pumps, controllers, etc., are not shown in this view so as notto obscure explanation of these high-level aspects of the invention.During a fluid exchange cycle, an amount of working fluid 319 flows intoan interior of second container 324 (compare FIG. 3A and FIG. 3B). Asshown in FIG. 3B, there is now a greater amount of working fluid 326 ain second container 324 a than there is in first container 316 a. Thewarming of working fluid 319 a in first container 316 a and cooling ofworking fluid 326 a in second container 324 a can be switched after afluid-exchange cycle so that the working fluid in first container 316 ais cooled while the working fluid in second container 324 a is warmed,which can give rise to another fluid-exchange cycle, and so on for anindefinite number of subsequent fluid-exchange cycles.

The state of flip-flopping the cooling and heating of both containers isshown in FIG. 3C where a supply of warmer HTF 312 b is allowed to warmworking medium 326 b while a supply of cooler HTF 312 b is used to coolworking medium 319 b from the interior of first container 316 b.

FIG. 3D illustrates an embodiment where circulation member 318 c forms apart of an interior wall of first container 316 c rather than beingdisposed further within first container 316 c as shown in FIG. 3A. Alsoshown in FIG. 3D is that heat-conducting structure 322 c may form aportion of an interior wall of second container 324 c as opposed tomerely being disposed within second container 324 c as shown in FIG. 3A.

Turning now to FIG. 4A, another simplified view of a high-level overviewof the present invention is shown in which the active heating andcooling of the working medium takes places within only one of a pair ofcontainers. Various valves, pumps, controllers, etc., are not shown inthis view so as not to obscure explanation of these high-level aspectsof the invention. As will be discussed later, FIG. 4A illustrates thebeginning of a phase equivalent to the end of that illustrated in FIG.4D. In this embodiment, warmer HTF 412 is circulated throughheat-conducting structure 414 in an interior of first container 416 towarm working fluid 419. Heat energy is transferred from warmer HTF 412into working fluid 419 which, in turn, results in an increase in thepressure of working fluid 419. FIG. 4B illustrates the effects of theincrease in pressure within first container 416 a, as a fluid exchangehas taken place and an amount of working fluid 419 a has flowed from aninterior of first container 416 a to an interior of second container 424a.

Turning now to FIG. 4C, a supply of cooler HTF 420 b is circulatedthrough heat-conducting structure 414 b in an interior of firstcontainer 416 b to cool working medium 419 b inside first container 416b. Heat energy is absorbed from working fluid 419 b into cooler HTF 420b which, in turn, results in a decrease in the pressure of working fluid419 b. FIG. 4D illustrates the effects of the decrease in pressurewithin first container 416 c, as a fluid exchange has taken place and anamount of working fluid 426 c has flowed from an interior of secondcontainer 424 c to an interior of first container 416 c. As wasmentioned previously, the end of the phase illustrated in FIG. 4D isequivalent to that illustrated in the beginning of that illustrated inFIG. 4A. A repetition of the process described can give rise to anindefinite number of subsequent fluid-exchange cycles.

Turning now to FIG. 5, an illustrative method for operating anembodiment of the present invention is provided and referenced generallyby the numeral 500. At a step 510, a determination is made as to whethera sufficiently high pressure differential between the two containersexists. With reference to FIG. 2A, in one embodiment, controller 252determines whether a sufficiently high pressure differential exists. Athreshold pressure differential could be preprogrammed or determined onthe fly. In alternative embodiments, the pressure differential can bedetermined in real time to be sufficiently high to begin afluid-exchange cycle. If a sufficiently high pressure differentialbetween two or more containers as the case may be does not exist, then astep 512 persists wherein the temperature within one or more of thecontainers is internally varied so as to increase the pressuredifferential between the two containers. For example, more heat may betransferred to one container, and/or heat may be withdrawn from theother container, and/or both of these may occur at the same time. In oneembodiment, heat transfer is facilitated by circulating heat-transferfluid as previously described. In alternative embodiments, an ignitablefluid may be ignited within a container to generate heat in thatcontainer.

Step 512 of internally varying the temperature within one or more of thecontainers persists until a sufficiently high pressure differential withrespect to two containers (for example) exists. This is indicated byarrow 514 reverting back to an illustrative determination step regardingthe extent of the pressure differentials between the two containers.

But if a sufficiently high pressure differential does exist between thecontainers at a step 510, then the illustrative process will advance tostep 516, wherein the working fluid is allowed to be exchanged from onecontainer to the other and as it does it performs work, or generateselectricity. In one embodiment, allowing the working fluid to beexchanged from one container to the other may include opening a fluidexchange valve, such as main valve 250 of FIG. 2A and allowing theworking fluid under relatively higher pressure to flow into thecontainer having a relatively lower pressure. As the working fluid flowsfrom one container to the other, turbine 270 and generator 272 arestimulated, which, in turn, can be used to generate electricity.

The fluid-exchange cycle is allowed to persist for as long as athreshold pressure differential between the two containers exists. Thisthreshold pressure differential may be monitored by controller 252 inone embodiment. Thus, at a step 518, a determination is made as towhether a sufficiently low pressure differential exists between the twocontainers to stop a fluid-exchange cycle. If not, then thefluid-exchange cycle of step 516 is allowed to persist as fluid movesfrom a higher-pressure environment to a lower-pressure environment. Butif the pressure differential between the two tanks has reduced to asufficiently lower amount, then the process reverts to step 512, whereinthe working fluid is prevented from being exchanged between the twocontainers. In one embodiment, this is accomplished by closing afluid-exchange valve such as main valve 250 as shown in FIG. 2A. Withthis valve closed, fluid is not allowed to be exchanged between the twocontainers, and the temperature associated with each of the respectiveworking mediums may be internally varied so as to rebuild back up apressure differential between the two containers that can be used tomotivate subsequent fluid-exchange cycles. In this way, an indefinitenumber of fluid-exchange cycles can occur, each of which generateselectricity. Turbine 270 may also be referred to as an energy converterbecause it converts a first type of energy into a second type of energy.If electricity is the desired end product, and turbine 270 cannot byitself generate electricity, then turbine 268 in connection withgenerator 272 may be referred to as an energy converter as they convertmechanical energy into electrical energy.

FIG. 6 illustrates still another illustrative operating environmentsuitable for practicing an embodiment of the present invention. In thisillustration, greater detail is shown as well as additional featuressuch as utilizing multiple containers to reduce the time betweenfluid-exchange cycles. Four containers are shown instead of two toillustrate the general concept; however, a larger number of containerscould be used so as to provide a continuously rotating turbine thatcontinuously generates electricity. The following description isprovided with reference to FIG. 6.

An HTF pump 10 a stimulates cyclical movement of a hotter HTF 12 from ahotter HTF supply reservoir 14 through an HTF valve system 16 through anHTF flow path 18 a causing hotter HTF 12 to pass through a solarradiation receiver tube 20. A reflecting device, such as a parabolicmirror 22 or similar light/heat-focusing device is positioned so that itreflects solar radiation onto solar radiation receiver tube 20, causinghotter HTF 12 within solar radiation receiver tube 20 to absorb heatenergy.

Other components can be utilized to facilitate varying heat levels ofhotter HTF 12. Describing all such components would be impractical, buta few are mentioned as illustrative. These components can be used as aprimary source of heat energy, especially when solar exposure to mirror22 is unavailable or impeded. They may also be used as a source of heatenergy prior to the passage of hotter HTF 12 through HTF flow path 18 ato preheat the HTF. Still again, these components may provide a sourceof additional heat energy after the passage of hotter HTF 12 through HTFflow path 18 a to post-heat the HTF. Illustrative such componentsinclude a natural gas heater 24 and a natural gas heat pump 26 with anatural gas supply 28 or heat storage reservoir 30.

Hotter HTF 12 can be stimulated by HTF pump 10 b through HTF flow path18 b. When natural gas heater 24 is operational, it burns natural gasfrom natural gas supply 28 and heat energy is transferred from naturalgas heater 24 into hotter HTF 12.

Hotter HTF 12 can be stimulated by pump 10 c through flow path 18 c.When natural gas heat pump 26 is operational, natural gas heat pump 26burns natural gas from natural gas supply 28 and heat energy istransferred from natural gas heat pump 26 into natural gas heat pump hotreservoir 32 and, in turn, into hotter HTF 12.

To conserve heat energy for later use if desired, previously heatedhotter HTF 12 can be stimulated by pump 10 d through flow path 18 dthrough a heat storage reservoir 30. In one embodiment, the temperatureof the hotter HTF 12 is hotter than the working medium within heatstorage reservoir 30 and, therefore, heat energy is transferred fromhotter HTF 12 into the working medium within reservoir 30.

Such working medium within reservoir 30 could be any suitable material,such as salt, resulting in heated salt or molten salt. When heat energyis needed to be extracted from reservoir 30, hotter HTF 12 can again bestimulated by pump 10 d through flow path 18 d through reservoir 30.Because heat is being extracted, the temperature of hotter HTF 12 iscooler than the working medium within heat storage reservoir 30 in thisembodiment. Heat energy is transferred from the working medium intohotter HTF 12.

Any available source of heat energy, whether from a storage facility,such as heat storage reservoir 30, or an arrangement such as parabolicmirror 22 and solar radiation receiver tube 20, natural gas heater 24,natural gas heat pump 26, or other sources such as industrial heat (notillustrated) can be used individually or in combination with one anotherto manipulate heat energy in hotter HTF 12. Even ambient environmentalheat (not illustrated) can be used if the ambient temperature is warmenough to raise the temperature within hotter HTF 12.

An HTF pump 10 e stimulates the cyclical movement of a cooler HTF 34from a reservoir 36 through a valve system 16 through a fluid flow path18 e causing the cooler HTF 34 to pass through geothermal cooling system38, causing the temperature of cooler HTF 34 to adjust toward thetemperature within cooling system 38.

Other components may be utilized to reduce the heat energy of cooler HTF34 according to various embodiments of the present invention. Thesecomponents can be as primary sources of reductions in heat energy, as asource of reductions in heat energy prior to (pre-cooling) the passageof cooler HTF 34 through geothermal cooling system 38, or as a source ofadditional reductions in heat energy after (post-cooling) the passage ofcooler HTF 34 through HTF geothermal cooling system 38. Included in anembodiment in regard to pre-cooling, post-cooling, or alternativecooling sources are natural gas heat pump 26 with natural gas supply 28,and a geothermal cooled reservoir 40.

Cooler HTF 34 can be stimulated by a pump 10 f through a flow path 18 f.When natural gas heat pump 26 is operational, it burns natural gas fromnatural gas supply 28. Heat energy is reduced within natural gas heatpump cold reservoir 42 and, in turn, within cooler HTF 34.

To conserve a supply of cooler HTF 34 in anticipation of later use,previously cooled cooler HTF 34 can be stimulated by pump 10 g intogeothermal cooled reservoir 40. Cooler HTF 34 can be extracted fromgeothermal cooled reservoir 40 via HTF pump 10 h.

Any available mechanism or method to reduce heat energy may be utilized.A storage facility, such as geothermal cooled reservoir 40, may beutilized as well as an active source of reductions in heat energy, suchas natural gas heat pump 26, or passive heat reductions, such as HTFgeothermal cooling system 38. Various components and methods can be usedindividually or in combination with one another to reduce the heatenergy in cooler HTF 34. Even ambient environmental cooling (notillustrated) can be used if the ambient temperature is cool enough toeffect a reduction of temperature within cooler HTF 34.

In one embodiment, the operation includes four primary phases: a firsttemperature-changing phase, a first fluid-exchange phase, a secondtemperature-changing phase, and a second fluid-exchange cycle. Thefollowing is an illustrative description of the phases.

During Phase I, heat energy is added to a working fluid in a container.Examples of a working fluid include air, dry air, or other primarilygaseous substance that responds to a rise in temperature with a rise inpressure. The introduced heat causes the pressure associated with theworking fluid to increase.

Phase II primarily involves the transfer of working fluid from thecontainer, stimulating a motive power device. This transfer of workingfluid out of the container causes a lowering of the pressure of theworking fluid within the container.

Phase III primarily involves the lowering of the temperature of theremaining working fluid within the container resulting in a furtherlowering of pressure.

Phase IV primarily involves the transfer of working fluid from higherpressure sources into the subject container.

In one embodiment, container 44 a principally illustrates the operationsof Phase I; container 44 b principally illustrates Phase II; container44 c principally illustrates Phase III; and container 44 d principallyillustrates Phase IV. Although the pressure of the working medium withineach of the containers in some embodiments will likely remainsignificantly above normal ambient pressure throughout the four phases,three levels of pressure will be referenced: moderate, heightened, andlowered (relatively). These correspond to the outline of operations justdescribed.

Container 44 a contains working fluid 46 a under pressure. At the startof Phase I, the pressure of working fluid 46 a within container 44 a maybe relatively moderate (see the above pressure scheme) and equivalent tothe end of Phase IV, which will be discussed in greater detail below.During Phase I, HTF pump 10 i stimulates the cyclical movement of hot(although references to “hot” or “cool” may be made herein, suchreferences make reading easier, but actually are relative terms; e.g.,“hotter than at a prior state or in another container” or “cooler thatat a prior state or in another container) HTF fluid 12 through flow path18 g, including internal heating and cooling conduit 48 a—disposedwithin the internal working fluid chamber of container 44 a—and HTFpressure regulator 50 a.

As hot HTF passes through internal heating and cooling conduit 48 a,conduit 48 a heats up, which, in turn, transfers heat to working fluid46 a in container 44 a. The increased temperature of the working fluid46 a in container 44 a causes an increase in pressure of the workingfluid 46 a in container 44 a.

In one embodiment, fans 52 a and 52 b in container 44 a may provideforced convection between internal heating and cooling conduit 48 a andthe working fluid 46 a in container 44 a via the circulation of workingfluid 46 a in container 44 a in the direction of the illustrativearrows. Of course the path may be in a different direction. Even still,there may be no circulation in embodiments that do not use such fans.

A controller 54 monitors the temperature of the hot HTF via temperaturegauges 56 a and 56 b in one embodiment. Controller 54 also monitors thetemperature and pressure of working fluid 46 a in container 44 a viaworking fluid temperature gauge 58 a and working fluid pressure gauge 60a, respectively. Controller 54 periodically manages the operations ofHTF pump 10 i and HTF pressure regulator 50 a so as to maintain a closerelationship between the fluid pressure of the hotter HTF 12 withininternal heating and cooling conduit 48 a and the fluid pressure of theworking fluid 46 a in container 44 a. Connections between controller 54and other devices have been omitted.

This function described of closely balancing the pressure of hotter HTF12 within internal heating and cooling conduit 48 a with the static orchanging pressure of the working fluid 46 a in container 44 a bymanipulating the fluid pressure of hotter HTF 12 within internal heatingand cooling conduit 48 a via the management of HTF pressure regulator 60a and information from HTF temperature gauges 56 a and 56 b and ofworking fluid pressure gauge 56 a, will hereinafter be referred to as“pressure balancing”.

In embodiments that require pressure balancing (as some do not,depending on the level and strength of available materials and the levelof desired efficiency), it will be present in its equivalent formsduring all phases described (for that embodiment). The primary purposeof pressure balancing, when included, is to minimize the requiredpressure tolerances and, therefore, the thickness of the materials,likely copper or other highly heat-conductive materials, used for theconstruction of internal heating and cooling conduit 48 a or itsequivalent.

Inner wall insulation 62 a is disposed on the inner wall of container 44a primarily in an effort to minimize the amount of heat energytransferred to or through container 44 a. As previously mentioned,intentional temperature manipulations of the working fluid occurinternally; that is, from within the containers, rather than by way ofexternal factors (factors external to the containers).

Emergency pressure relief valve 64 a is included with container 44 a incase of malfunctions or unanticipated pressures that would otherwisecompromise the integrity of container 44 a or any of the otherapplicable components in one embodiment.

Working fluid transfer valve 66 a and working fluid transfer conduit 68a, controlled by controller 54, are included with container 44 a. DuringPhase I, they remain in a closed position. The primary functions ofworking fluid transfer valve 66 a and working fluid transfer conduit 68a will be explained in connection with the discussions of the remainingphases to follow.

Geothermal working fluid valves 70 a and 70 b, which, during Phase I,remain in a closed position, geothermal working fluid cooling flow path72 a, geothermal working fluid cooling system 74 a, working fluidtemperature gauge 58 b, working fluid pressure gauge 60 b, and emergencypressure relief valve 64 b are included with container 44 a in oneembodiment. The primary functions of geothermal working fluid valves 70a and 70 b, geothermal working fluid cooling flow path 72 a, geothermalworking fluid cooling system 74 a, working fluid temperature gauge 58 b,working fluid pressure gauge 60 b, and emergency pressure relief valve64 b will be explained within the discussions of the remaining phases tofollow.

When the temperature and pressure of working fluid 46 a within container44 a reach desired levels, Phase II begins in this embodiment. Container44 b is assumed to have previously transitioned through Phase I and,therefore, contains working fluid 46 b under a relatively heightenedfluid pressure.

Optionally, just as in Phase I, during Phase II, HTF pump 10 j couldcontinue to stimulate the cyclical movement of hotter HTF 12 throughinternal HTF flow path 18 h, including internal heating and coolingconduit 48 b, disposed within the internal working fluid chamber ofcontainer 44 b, and HTF pressure regulator 50 b, which could continue toadd heat energy to working fluid 46 b. Similarly, fans 52 c and 52 d,disposed within container 44 b, can continue to provide forcedconvection between internal heating and cooling conduit 48 b and theworking fluid 46 b in container 44 b via the circulation of workingfluid 46 b in container 44 b.

Controller 54 monitors the temperature of the hotter HTF 12 via HTFtemperature gauges 56 c and 56 d. Controller 54 also monitors thetemperature and pressure of the working fluid 46 b in container 44 b viaworking fluid temperature gauge 58 b and working fluid pressure gauge 60b, respectively. Controller 54 periodically manages the operations ofHTF pump 10 j and HTF pressure regulator 50 b so as to maintain a closerelationship between the fluid pressure of the hotter HTF 12 withininternal heating and cooling conduit 48 b and the fluid pressure of theworking fluid 46 b in container 44 b.

Inner wall insulation 62 b is disposed on the inner wall of container 44b primarily in an effort to minimize the amount of heat energytransferred to or through container 44 b. Emergency pressure reliefvalve 64 c is included with container 44 b in case of malfunctions orunanticipated pressures that would otherwise compromise the integrity ofcontainer 44 b or any of the other applicable components.

Working fluid transfer valve 66 b and working fluid transfer conduit 68b, controlled by controller 54, are included with container 44 b.Characteristic of Phase II, working fluid transfer valve 66 b is openedand working fluid 46 b is allowed to flow from container 44 b throughworking fluid transfer conduit 68 b to working fluid valve system 76where the working fluid 46 b from container 44 b is routed through airturbine flow path 78, working fluid pressure regulator 80, air turbine82, and post-turbine geothermal working fluid cooling system 84.

Working fluid pressure regulator 80, controlled by controller 54,manages the fluid pressure of the working fluid 46 b passing toward airturbine 82. Subject to the operation of working fluid pressure regulator80, as working fluid 46 b passes through air turbine 82, the workingfluid 46 b causes air turbine 82 to react, generating motive power untilthe net pressure differential between the working fluid 46 b on theentry side of air turbine 82 and the working fluid 46 b on the exit sideof air turbine 82 is equal to or less than the minimum pressuredifferential required to stimulate air turbine 82 and related loads.

Generator 86 is coupled to air turbine 82 in order to generateelectricity in response to the motive power of air turbine 82. Followingthe exit of working fluid 46 b from container 44 b, the pressure ofworking fluid 46 b still within container 44 b is reduced from itsrelatively heightened level, referred to afterwards as moderate, inreference to the previously discussed pressure scheme. Generator 86 maybe part of turbine 82.

As working fluid 46 b passes through post-turbine geothermal workingfluid cooling system 84, the working fluid 46 b adjusts toward thetemperature within post-turbine geothermal working fluid cooling system84. Geothermal working fluid valves 70 c and 70 d, which, during PhaseII, remain in a closed position, geothermal working fluid cooling flowpath 72 b, geothermal working fluid cooling system 74 b, working fluidtemperature gauge 58 d, working fluid pressure gauge 60 d, and emergencypressure relief valve 64 d are included with container 44 b. The primaryfunctions of geothermal working fluid valves 70 c and 70 d, geothermalworking fluid cooling flow path 72 b, geothermal working fluid coolingsystem 74 b, working fluid temperature gauge 58 d, working fluidpressure gauge 60 d, and emergency pressure relief valve 64 d will beexplained within the discussions of the remaining phases to follow.

When the pressure of working fluid 46 b within container 44 b reaches adesired level, working fluid transfer valve 66 b is closed by controller54 and Phase III could commence. Container 44 c is assumed to havepreviously transitioned through Phase I and Phase II and, therefore,contains working fluid 46 c again at a relatively moderate fluidpressure, in reference to the previously discussed pressure scheme.

During Phase III, HTF pump 10 k stimulates the cyclical movement ofcooler HTF 34, cooled by one of the components or methods of heatreduction discussed previously or other device or method, through HTFflow path 18 i, including internal heating and cooling conduit 48 c,disposed within the internal working fluid chamber of container 44 c,and HTF pressure regulator 50 c.

As cooler HTF 34 passes through inner internal heating and coolingconduit 48 c, internal heating and cooling conduit 48 c cools down and,in turn, heat is transferred from the working fluid 46 c in container 44c.

Geothermal working fluid valves 70 e and 70 f, controlled by controller54, geothermal working fluid cooling flow path 72 c, geothermal workingfluid cooling system 74 c, working fluid temperature gauge 58 e, workingfluid pressure gauge 60 e, and emergency pressure relief valve 64 e areincluded with container 44 c. When desired, controller 54 opensgeothermal working fluid valve 70 e and the remaining pressure withinthe working fluid 46 c remaining within container 44 c may force aportion of the working fluid 46 c remaining within container 44 c intogeothermal working fluid cooling flow path 72 c [optionally, a turbineor other energy converter (not illustrated) could be placed at or nearthe beginning of geothermal working fluid cooling flow path 72 c tocapture a portion of the energy provided by the fluid initially flowinginto geothermal working fluid cooling flow path 72 c motivated by anyexcess pressure of the working fluid 46 c remaining within container 44c as compared to the fluid already resident in the geothermal workingfluid cooling flow path 72 c]. Thereafter, when desired, usinginformation from working fluid pressure gauge 60 c, disposed withcontainer 44 c, and working fluid pressure gauge 60 e, disposed withgeothermal working fluid cooling flow path 72 c, controller 54 opensgeothermal working fluid valve 70 e which, in turn, opens working fluidcooling flow path 72 c through geothermal working fluid cooling system74 c.

Fans 52 e and 52 f, disposed within container 44 c, stimulate themovement of the working fluid 46 c remaining within container 44 c intoworking fluid flow path 72 c by blowing the working fluid 46 c remainingwithin container 44 c in the direction of the illustrative arrows(alternately, force could also be provided in the opposite direction).Working fluid 46 c remaining within container 44 c is, to the extentpossible and practical, replaced by working fluid exiting geothermalworking fluid cooling system 74 c.

The combination of the cooling of internal heating and cooling conduit48 c and the stimulation of movement of the working fluid 46 c remainingwithin container 44 c into working fluid flow path 72 c and, in turn,the stimulation of working fluid 46 c from geothermal working fluidcooling system 74 c into container 44 c, results in a decreasedtemperature of the working fluid 46 c in container 44 c than at thestart of Phase III which, in turn, results in a lowered pressure of theworking fluid 46 c in container 44 c.

Controller 54 monitors the temperature of the cooler HTF 34 via HTFtemperature gauges 56 e and 56 f. Controller 54 also monitors thetemperature and pressure of the working fluid 46 c in container 44 c viaworking fluid temperature gauge 58 c and working fluid pressure gauge 60c, respectively. Controller 54 also monitors the temperature andpressure of the working fluid 46 c entering container 44 c fromgeothermal working fluid cooling system 74 c via working fluidtemperature gauge 58 e and working fluid pressure gauge 60 e,respectively. Controller 54 periodically manages the operations of HTFpump 10 k and HTF pressure regulator 50 c so as to maintain a closerelationship between the fluid pressure of the cooler HTF 34 withininternal heating and cooling conduit 48 c and the fluid pressure of theworking fluid 46 c in container 44 c.

Inner wall insulation 62 c is disposed on the inner wall of container 44c primarily in an effort to minimize the amount of heat energytransferred to or through container 44 c. Emergency pressure reliefvalve 64 f is included with container 44 c in this embodiment in case ofmalfunctions or unanticipated pressures that would otherwise compromisethe integrity of container 44 c or any of the other applicablecomponents. Emergency pressure relief valve 64 e is included withworking fluid flow path 72 c in case of malfunctions or unanticipatedpressures that would otherwise compromise the integrity of working fluidflow path 72 c or any of the other applicable components.

Working fluid transfer valve 66 c and working fluid transfer conduit 68c, controlled by controller 54, are included with container 44 c, and,during Phase III, remain in a closed position. The functions of workingfluid transfer valve 66 c and working fluid transfer conduit 68 c werepartially explained within the discussions of Phase II and will becontinued within the discussions of Phase IV.

When the temperature and pressure of working fluid 46 c within container44 c reach desired levels, geothermal working fluid valves 70 e and 70 fcan be closed by controller 54, and Phase IV could commence.

Container 44 d is assumed to have previously transitioned through PhasesI through III and, therefore, contains working fluid 46 d at a loweredfluid pressure. Optionally, just as in Phase III, during Phase IV, HTFpump 10 l could continue to stimulate the cyclical movement of coolerHTF 34 through HTF flow path 18 j, including internal heating andcooling conduit 48 d, disposed within the internal working fluid chamberof container 44 d, and HTF pressure regulator 50 d, which could continueto reduce the heat energy within the working fluid 46 d within container44 d. Fans 52 g and 52 h, disposed within container 44 d, can provideforced convection between internal heating and cooling conduit 48 d andthe working fluid 46 d in container 44 d via the circulation of workingfluid 46 d in container 44 d in the direction of the illustrative arrows(a circulatory path could also be attained in the opposite direction).

Controller 54 monitors the temperature of the cooler HTF 34 via HTFtemperature gauges 56 g and 56 h. Controller 54 also monitors thetemperature and pressure of the working fluid 46 d in container 44 d viaworking fluid temperature gauge 58 g and working fluid pressure gauge 60g, respectively. Controller 54 periodically manages the operations ofHTF Pump 10 l and HTF pressure regulator 50 d so as to maintain a closerelationship between the fluid pressure of the cooler HTF 34 withininternal heating and cooling conduit 48 d and the fluid pressure of theworking fluid 46 d in container 44 d.

Inner wall insulation 62 d is disposed on the inner wall of container 44d primarily in an effort to minimize the amount of heat energytransferred to or through container 44 d. Emergency pressure reliefvalve 64 g is included with container 44 d in case of malfunctions orunanticipated pressures that would otherwise compromise the integrity ofcontainer 44 d or any of the other applicable components.

Geothermal working fluid valves 70 g and 70 h, controlled by controller54, geothermal working fluid cooling flow path 72 d, geothermal workingfluid cooling system 74 d, working fluid temperature gauge 58 g, workingfluid pressure gauge 60 g, and emergency pressure relief valve 64 g areincluded with container 44 d. The primary functions of geothermalworking fluid valves 70 g and 70 h, geothermal working fluid coolingflow path 72 d, geothermal working fluid cooling system 74 d, workingfluid temperature gauge 58 g, working fluid pressure gauge 60 g, andemergency pressure relief valve 64 g were explained within thediscussions of the previous phases.

Working fluid transfer valve 66 d and working fluid transfer conduit 68d, controlled by controller 54, are included with container 44 d.Characteristic of Phase IV, working fluid transfer valve 66 d is openedand working fluid 46 d is allowed to flow into container 44 d fromworking fluid transfer conduit 68 d from working fluid valve system 76where the working fluid 46 d into container 44 d is routed from airturbine flow path 78. The origination of the flow of working fluid 46 dis from one or more containers operating in Phase II of the four phasecycle.

When the pressure of working fluid 46 d within container 44 d reaches adesired level, referred to here as moderate in reference to the abovepressure scheme, working fluid transfer valve 66 d is closed bycontroller 54, and Phase I could commence.

Detailed drawings of HTF valve system 16 and working fluid valve system76 were omitted from FIG. 5. The working of these valve systems areroutine and have been represented by generic shapes which represent asufficient array of conduits and valves to direct the flow of fluids asdirectly and indirectly described in this detailed description of theinvention.

In the above description, various valves were to be controlled bycontroller 54, and various gauges were to provide information tocontroller 54. But some embodiments do not require all of these gaugesand valves. Certain valves that automatically open after being subjectedto a threshold pressure may be used. HTF temperature gauges 56 i through56 v are included to provide information to controller 54 so thatcontroller 54 can monitor the temperature of HTFs 12 and 34 in order tooptimize operations and the phases for each container in one embodiment.Similarly, working fluid temperature gauges 58 i through 58 n andworking fluid pressure gauges 601 through 60 n are included to provideinformation to controller 54 so that controller 54 can monitor thetemperature and pressure of the working fluid 46 d within the workingfluid transfer conduits 68 a through 68 d and air turbine flow path 78in order to optimize operations and the phases for each container.Emergency pressure relief valves 641 through 64 n are included withworking fluid transfer conduits 68 a through 68 d and air turbine flowpath 78 in case of malfunctions or unanticipated pressures that wouldotherwise compromise the integrity of working fluid transfer conduits 68a through 68 d and air turbine flow path 78 or any of the otherapplicable components.

The shape of internal heating conduits 48 a through 48 d could vary, asthe goal of the conduits is the transfer of heat energy to and from theworking fluid 46 d within containers 44 a through 44 d, depending on thephase in process. One shape of particular interest, not illustrated, maybe that of a coil across the cross-section of the containers, so thatthe forced convection currents will cause working fluid 46 d to passvery close to a portion of the coil. There may be one or more heatingconduits within a given container in order to provide a faster rate ofheat transfer.

The cooling of working fluid 46 d within post-turbine geothermal workingfluid cooling system and during the operations of Phase III add to thedevelopment of the potential energy between the relatively heightenedpressure levels at the end of Phase I and the lowered pressure levels atthe end of Phase III, just as the adding of heat energy to working fluid46 d during Phase I adds to the development of the potential energy.This potential energy, resulting from the contrast and use of bothadditional heat energy and reductions of heat energy, is particularlyadaptive to the use of heat pump technologies. Many heat pumpapplications emphasize the use of only the “hot end” or the “cold end”of the heat pump. The present invention is capable of making use of theentire cycle of heat pump technology and, therefore, may be particularlyefficient in the use of the energy consumed by the heat pump.

In order to minimize the heat conducted into the materials used for theconstruction of the working fluid conduits or other components,insulation could be included on the outside or the inside of theconduits, or both, or other components, as a heat conduction barrier,where appropriate.

In one embodiment, in order to attempt to capture a portion of the heatenergy remaining within internal heating and cooling conduit 48 c andworking fluid 46 c at the start of Phase III (from the end of phase II),an initial portion of the cooler HTF 34 used in phase III, warmed bysuch remaining heat energy, may be subjected to one or more of theprocesses used to heat or reheat hotter HTF 12 and combined with hotterHTF 12 within such processes (for use in subsequent phases I and II).

Other embodiments, either more complex or refined or simpler arepossible. For instance, the description above includes a computercontroller to operate an array of valves and consider information froman array of gauges. Further, emergency pressure relief valves areincluded and several of the conduits and other parts are insulated tominimize heat losses. However, many of these components are optional.

An array of only four containers, one air turbine, and one generator wasdescribed with reference to FIG. 6. But as mentioned, a larger number ofcontainers is probable for more continuous operations and a largernumber of other components is possible. For instance, if a larger numberof containers are included, the initiation of the four phases could bestaggered so that a reasonably consistent and steady flow of workingfluid could be maintained through the air turbine, which may alleviatethe need for a pressure regulator in regard to the flow of workingfluid.

Turning now to FIG. 7, another simplified view of a high-level overviewof an embodiment of the present invention is shown. In this embodiment,warmer HTF 712 is motivated through valve 782 into the interior of firstcontainer 716. In some embodiments pump 718 can be utilized to motivateHTF 712 to flow into the interior via interior heat-transfer component714 to warm working fluid 719. In this embodiment, the warmer HTF 712 isallowed to come into direct contact with working fluid 719 and totransfer heat without being contained in a conduit or other component.

Heat transfer component 714, in this embodiment, can be a port, or anozzle-type component protruding through a void in first container 716that is sufficient for the introduction of warmer HTF 712 (in someembodiments, warmer HTF 712 may be superheated). In this embodiment,excess HTF 712 may accumulate at or near an HTF exit area, where valve788 is included to control an accumulation of HTF 712.

A supply of cooler HTF 720 is motivated through valve 784 (by pump 734in some embodiments) and into the interior of second container 724 viainterior heat-transfer component 722 to cool working fluid 726. Variousvalves, pumps, controllers, etc., are not shown in this view so as notto obscure explanation of these high-level aspects of the invention. Forinstance, a layer of insulation may be included (as with otherembodiments) to reduce the transfer of heat between working fluid 719and first container 716 or between HTF 712 and first container 716.

As working fluid 719 within first container 716 warms, and working fluid726 within second container 724 cools, working fluid 719 is motivated tomove in the direction indicated which, in turn, motivates working fluidto pass through energy converter 770 and stimulate generator 772, if itis different than energy converter 670.

Alternating the heating and cooling of the working fluid within thefirst and second containers can lead to further working-fluid exchangecycles in both directions.

Turning now to FIG. 8, another simplified view of a high-level overviewof an embodiment of the present invention that includes a piston 870 asa type of energy converter is shown. As in the embodiment justmentioned, this embodiment contemplates warmer HTF 812 being motivatedthrough valve 882 (by pump 818 in some circumstances) and into theinterior of first container 816 via interior heat-transfer component 814to warm working fluid 819. Again, HTF 812 is allowed to come into directcontact with working fluid 819. The heat transfer component 814, in thisembodiment, may be a port or nozzle-type component or just be a void infirst container 816. Valve 888 can be included to control anaccumulation of HTF 812. A supply of cooler HTF 820 is motivated throughvalve 884 by pump 834 and into the interior of second container 824 viainterior heat-transfer component 822 to cool working fluid 826.

As working fluid 819 within first container 816 warms and working fluid826 within second container 824 cools, the resulting pressuredifferential between working fluids 819 and 826 results in a force thatmotivates piston 870, which stimulates shaft 872. Piston 870 and itscoupling to shaft 872 are meant to be shown schematically. Alternatingthe heating and cooling of the working fluid within the first and secondcontainers can lead to further working fluid exchange cycles in bothdirections.

Many different arrangements of the various components depicted, as wellas components not shown, are possible without departing from the spiritand scope of the present invention. For example, the geothermal workingfluid cooling system 74 c and related components from FIG. 6 could beused to cool working fluid 826 within second container 824 instead or incombination with cooler HTF 820 and its related components above.

In the embodiments discussed above, various methods and systems weredescribed to effect heat transfer from the heat-transfer fluid to theworking fluid. Many of these embodiments contemplate an indirectheat-transfer process. That is, some medium contained the heat-transferfluid, and by virtue of conduction, convection or a combination thereof,heat is transferred from the HTF to the medium containing the HTF andthen from the medium to the working fluid. In some of the illustrativeembodiments, this containing medium took the form of conduit. In otherembodiments, it takes the form of an inner wall having voids that HTFcould flow through.

But in still other embodiments, heat transfer may be facilitateddirectly (as mentioned above). That is, under appropriate conditions,the HTF itself can be introduced into the container(s) such that it isin direct communication with the working fluid so that heat from the HTFcan be directly communicated to the working fluid.

For example, the HTF may be introduced into a container from one or moreinlets into the containers. In some embodiments, the HTF may beintroduced as droplets. Any pressure exerted from an interior of acontainer may be overcome by utilizing a pump to motivate the HTF toflow into a chamber of the container. Any collection of HTF may bedischarged by way of a discharge valve. Examples of these embodimentswere shown in FIGS. 7 & 8. The process does not need to be continuous oreven regular, and it can be used alone or in combination with theaforementioned indirect-heating structures. For example, in someembodiments, the HTF may intentionally be allowed to sweat or to leakout of pores or other voids of the structures, such as conduit tubing,under certain conditions. An illustrative condition may include when thepressure within a container drops below a certain threshold. At thispoint, the HTF may be allowed to seep into a chamber. This may occur byvirtue of the relative pressure difference between an interior of theconduit and an interior of the container.

Embodiments of the present invention have been described with the intentto be illustrative rather than restrictive. Alternative embodiments willbecome apparent to those skilled in the art that do not depart from itsscope. A skilled artisan may develop alternative means of implementingthe aforementioned improvements without departing from the scope of thepresent invention.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations and are contemplated within the scope of the claims. Notall steps listed in the various figures need be carried out in thespecific order described. The use of the term “optionally” in someplaces is not meant to imply a necessity in other places where it is notused.

1. An energy-conversion apparatus, comprising: a first container tocontain working fluid under pressure; a first heat-transfer component inthe first container; a second container to contain working fluid underpressure; and an energy converter coupled to the first and secondcontainers that performs work in response to a flow of working fluidthrough the energy converter, wherein the flow is motivated by varying apressure within the first container caused by the first heat-transfercomponent.
 2. The apparatus of claim 1, wherein the first heat-transfercomponent is operable to internally manipulate an internal temperaturewithin the first container.
 3. The apparatus of claim 2, wherein thefirst heat-transfer component is operable to provide heat to or removeheat from an interior of the first container.
 4. The apparatus of claim3, wherein the first heat-transfer component includes one or more of: anarrangement of conduit in an interior cavity of the first container thatallows for a circulation of a heat-transfer fluid that facilities heattransfer; an interior wall of the container exposed to the interiorcavity, the interior wall including voids though which heat-transferfluid can be circulated; and an arrangement of conduit through whichworking fluid can flow and that is coupled to one or both of the firstand second containers, the arrangement allowing a geothermal process tobe utilized to effect heat transfer from or to the working fluid as itflows though the arrangement.
 5. The apparatus of claim 4, wherein theheat-transfer fluid includes a gas, a liquid, or combination thereof. 6.The apparatus of claim 5, wherein the heat-transfer fluid is capable ofbeing subjected to a temperature-changing process including one or moreof: utilizing solar energy to effect a temperature change; utilizinggeothermal heating or cooling to effect a temperature change; utilizinga heat pump to effect a temperature change; or utilizing an ignitablefuel source to effect the temperature change.
 7. The apparatus of claim6 wherein the ignitable fuel source is ignitable from within an interiorof the first or second containers.
 8. An energy-conversion apparatus,comprising: a first container to contain working fluid under pressure; afirst heat-transfer component in the first container that is operable tomanipulate an internal temperature of the first container (firstinternal temperature) from within the first container; a secondcontainer to contain working fluid under pressure; a secondheat-transfer component in the second container that is operable tomanipulate an internal temperature of the second container (secondinternal temperature) from within the second container; and an energyconverter coupled to the first and second containers that performs workin response to a flow of working fluid between the containers.
 9. Theapparatus of claim 8, wherein the first container is insulated.
 10. Theapparatus of claim 8, wherein the first heat-transfer component isfurther operable to internally manipulate the first internal temperaturesubstantially independently of an ambient temperature of an environment.11. The apparatus of claim 10, wherein the energy converter generateselectricity via rotational motion.
 12. The apparatus of claim 10,wherein the flow of the working fluid between the containers is urged bya difference in pressure within one of the containers compared to apressure within the other of the containers, wherein the difference inpressure is induced by varying one or more of the first or secondinternal temperatures utilizing one or more of the first or secondheat-transfer components.
 13. The apparatus of claim 8, wherein theenergy converter that performs work includes an energy converter thatcan be used to generate electricity.
 14. The apparatus of claim 8,wherein the flow of working fluid between the containers includes a flowfrom the first container to the second container or a flow from thesecond container to the first container.
 15. The apparatus of claim 8,further comprising a pressure-balancing component that reduces thepressure differential between the exterior of the first heat-transfercomponent and the interior of the first heat-transfer component below athreshold amount.
 16. An energy-conversion apparatus that utilizes aheat-transfer fluid (HTF), the apparatus comprising: a first containerto contain working fluid under pressure; a first inlet port that allowsHTF to be introduced into an interior of the first container; a secondcontainer to contain working fluid under pressure; and an energyconverter coupled to the first and second containers that performs workin response to a flow of working fluid through the energy converter,wherein the flow is motivated by internally varying a pressure withinthe first container caused by direct heat transfer between the HTF andthe working fluid.
 17. The apparatus of claim 16, further comprising asecond inlet port that allows HTF to be introduced into an interior ofthe second container.
 18. The apparatus of claim 16, further comprisingan arrangement of conduit through which working fluid can flow and thatis coupled to one or both of the first and second containers, thearrangement allowing a geothermal process to be utilized to effect heattransfer from or to the working fluid as it flows though thearrangement.
 19. An energy-conversion apparatus, comprising: a firstcontainer of working fluid under pressure; a second container of workingfluid under pressure coupled to the first container; a firstheat-transfer component in the first container that, without a need forheat conduction through an exterior surface of the first container, isoperable to perform one or more of (1) internally increase a temperaturewithin the first container above a temperature within the secondcontainer, and/or (2) internally decrease a temperature within the firstcontainer below a temperature within the second container; and an energyconverter coupled to the first container and to the second container andadapted to perform work in response to a force exerted upon it, theforce created as a result of a change in pressure in at least the firstcontainer caused by an internal manipulation of an internal temperaturewithin at least the first container.
 20. The apparatus of claim 19,further comprising a second heat-transfer component in the secondcontainer that is operable to internally manipulate an internaltemperature within the second container.
 21. The apparatus of claim 20,wherein, without a need for heat conduction through an exterior surfaceof the first container, the second heat-transfer component is operableto perform one or more of: internally increase a temperature within thesecond container above a temperature within the first container, and/orto internally decrease a temperature within the second temperature belowa temperature within the first container.
 22. The apparatus of claim 19,wherein the first heat-transfer component is operable to alternately:internally increase a temperature within the first container above atemperature within the second container or vice versa; and/or tointernally decrease a temperature within the first temperature below atemperature within the second container or vice versa.
 23. The apparatusof claim 19, wherein the energy converter includes a piston.
 24. Anenergy-conversion apparatus comprising: a first container to containworking fluid under pressure, the first container including an inletport; a second container to contain working fluid under pressure; and anenergy converter coupled to the first and second containers thatperforms work in response to a flow of working fluid through the energyconverter, wherein the flow is motivated by internally varying apressure within the first container caused by varying a temperature ofthe working fluid in at least the first container.
 25. The apparatus ofclaim 24, wherein the inlet port facilitates varying the temperature ofthe working fluid in the first container by directly exposing theworking fluid to an effect from burning an ignitable fuel source burningwithin the container.
 26. A method for converting energy by utilizing asystem comprising first and second containers to contain working fluidunder pressure coupled to an energy converter, the method comprising:from within one or both of the first and second containers, varying aninternal pressure; and performing work as the energy converter isstimulated in response to a flow of working fluid motivated to passthrough the energy converter by the varying internal pressure, whereinthe varying of the internal pressure comprises effecting a temperaturechange from within the first container, thereby causing a resultantchange in pressure.
 27. The method of claim 26, wherein varying theinternal pressure(s) of the container(s) comprises varying a temperatureof the working fluid by introducing a heat-transfer fluid into the firstand/or second container that is of such a temperature that can vary theinternal pressure of the container(s).
 28. The method of claim 27,wherein introducing the heat-transfer fluid includes varying atemperature of the heat transfer fluid;
 29. The method of claim 26,wherein varying the temperature of the heat-transfer fluid includes oneor more of: utilizing solar energy to effect a temperature change;utilizing geothermal heating or cooling to effect a temperature change;utilizing a heat pump to effect a temperature change; or utilizing anignitable fuel source to effect the temperature change.
 30. The methodof claim 26, wherein varying the internal pressure(s) of thecontainer(s) comprises varying a temperature of the working fluid byexposing the working fluid to an effect from burning an ignitable fuelsource burning within the container.
 31. A method for converting energyby utilizing a system comprising a first container to contain workingfluid under pressure coupled by way of an energy converter to a secondcontainer to contain working fluid under pressure, the methodcomprising: from within one or both of the first or second containers,varying an internal temperature to cause a resultant pressuredifferential that motivates the working fluid to flow between the firstand second containers; and performing work as working fluid flowsthrough the energy converter between the containers in response to thepressure differential.
 32. The method of claim 31, varying the internaltemperature includes introducing heat to or withdrawing heat from theworking fluid within the first or second containers.
 33. The method ofclaim 32, wherein the introducing or withdrawing heat includes one ormore of: exposing an interior of at least one of the containers to theeffects of a heat-transfer fluid; circulating a heat-transfer fluidthrough a portion of conduit in the first or second containers;utilizing a geothermal heating or cooling process; and introducing andigniting an ignitable fuel within the first or second containers. 34.The method of claim 33, wherein the exposing includes circulating theheat-transfer fluid through one or more cavities that includes at leastone surface that is in communication with the interior of the first orsecond containers.
 35. The method of claim 32, wherein the heat-transferfluid is subjected to a warming process prior to circulation through theone or more cavities.
 36. The method of claim 35, wherein the warmingprocess includes concentrating sunlight to a localized volume of theheat-transfer fluid.
 37. The method of claim 31, wherein the performingwork includes one or more of generating electricity, converting energyfrom a first form to another, and effecting motion.
 38. A method forconverting energy as working fluid flows between a first container thatcontains working fluid under pressure and a second container thatcontains working fluid under pressure, the method comprising stimulatingan energy converter by inducing a fluid-exchange cycle through theenergy converter by varying the pressure of at least one of thecontainers relative to the other by internally varying the temperatureof the working fluid of at least one of the containers.
 39. The methodof claim 38, wherein internally varying the temperature of the workingfluid of at least one of the containers includes internally varying thetemperature substantially independently of an ambient temperatureassociated with an ambient environment in which the first or secondcontainers are exposed.
 40. A method for converting energy, comprising:providing a first a container to contain working fluid under pressure,the first container substantially surrounding a first heat-transfercomponent that can internally change an internal temperature within thefirst container; providing a second container to contain working fluidunder pressure, the second container substantially surrounding a secondheat-transfer component that can internally change an internaltemperature within the second container; providing an energy convertercoupled to the first container and to the second container; stimulatingthe energy converter with a flow of working fluid from the firstcontainer to the second container by internally varying a pressurewithin the first or second container by varying a temperature within thefirst or second container so that a first pressure differential betweenthe two containers is sufficiently high that it motivates the flow untilthe differential pressure between the two containers reaches a desiredlow pressure differential; and increasing the desired low pressuredifferential to a second sufficiently high pressure differential so asto motivate a flow of the working fluid from the second container to thefirst container by varying a temperature within the first or secondcontainers.
 41. The method of claim 40, wherein the energy converterincludes an oscillating member.
 42. The method of claim 41, whereinstimulating the energy converter includes utilizing the working fluidwithin the first container to exert a force against the oscillatingmember.
 43. The method of claim 42, wherein utilizing the working fluidto exert the force against the oscillating member includes heating aheat-transfer fluid prior to it entering an interior of the firstcontainer.